Léder Leal Xavier

A Neurologia é um ramo da medicina que visa diagnosticar e tratar patologias relacionadas aos Sistemas Nervosos Central, Periférico e Autonômico (SNC, SNP, SNA). Nessa análise, é de extrema importância o desenvolvimento de um raciocínio clínico claro e objetivo para o reconhecimento de anomalias que possam prejudicar ou, até mesmo, colocar em risco a vida do indivíduo. Dessa forma, este capítulo tem como propósito auxiliar o estudante a esclarecer e a simplificar a elaboração do diagnóstico neurológico mais preciso possível, a partir de uma estratificação investigativa feita em três etapas: diagnóstico sindrômico, topográfico e etiológico, os quais serão elucidados a seguir. Alguns autores dividem a última etapa em diagnóstico nosológico e etiológico, sendo o primeiro o grupo de determinada doença (por exemplo, vascular ou infecciosa), e o último as diferentes condições dentro de cada uma (por exemplo, acidente vascular isquêmico ou meningite meningocócica).

A escassez de respiradores hospitalares durante a pandemia de COVID-19 comprometeu o atendimento de pacientes graves no Sistema Único de Saúde (SUS). Este relato de experiência descreve o desenvolvimento de uma tecnologia inovadora para oxigenoterapia, criada por um grupo interdisciplinar que atua na perspectiva do ensino-em-serviço. Foram produzidos 140 protótipos do “Conector Nasal de Alto Fluxo (CNAF) adaptado” por impressão 3D, com custo unitário de R$510,00. O dispositivo gerou um fluxo de 15 L/min de oxigênio, com possibilidade de ampliação para 30 L/min por um acréscimo de R$100,00. Sistemas comerciais completos de alto fluxo de oxigênio podem atingir R$25.000,00. A solução desenvolvida reduziu significativamente os custos e ampliou o acesso à oxigenoterapia no SUS, demonstrando o potencial da inovação tecnológica para otimizar recursos e melhorar a assistência em saúde.

Background. Stroke is a widespread and complex health issue, with many survivors requiring long-term rehabilitation due to upper-limb impairment. This study is aimed at comparing the perceived usability of two feedback-based stroke therapies: conventional mirror therapy (MT) and immersive virtual reality mirror therapy (VR). Methods. The study involved 45 participants, divided into three groups: the stroke survivors ( ), stroke-free older adults ( ), and young controls ( ). Participants performed two tasks using both MT and VR in a semirandom sequence. Usability instruments (SUS and NASA-TLX) were applied at the end of the activities, along with two experience-related questions. Results. The results indicated that both MT and VR had similar levels of perceived usability, with MT being more adaptable and causing less overall discomfort. Conversely, VR increased the perception of task difficulty and prevented participants from diverting their attention from the mirror-based feedback. Conclusion. While VR was found to be less comfortable than MT, both systems exhibited similar perceived usability. The comfort levels of the goggles may play a crucial role in determining the usability of VR for upper limb rehabilitation after stroke.

Environmental enrichment (EE) refers to different forms of stimulation, where the environment is designed to improve the levels of sensory, cognitive, and motor stimuli, inducing stroke recovery in animal models. Stroke is a leading cause of mortality and neurological disability among older adults, hence the importance of developing strategies to improve recovery for such patients. This review provides an update on recent findings, compiling information regarding the parameters affected by EE exposure in both preclinical and clinical studies. During stroke recovery, EE exposure has been shown to improve both the cognitive and locomotor aspects, inducing important neuroplastic alterations, increased angiogenesis and neurogenesis, and modified gene expression, among other effects. There is a need for further research in this field, particularly in those aspects where the evidence is inconclusive. Moreover, it is necessary refine and adapt the EE paradigms for application in human patients.

Human infection by the SARS-CoV-2 is causing the current COVID-19 pandemic. With the growing numbers of cases and deaths, there is an urgent need to explore pathophysiological hypotheses in an attempt to better understand the factors determining the course of the disease. Here, we hypothesize that COVID-19 severity and its symptoms could be related to transmembrane and soluble Angiotensin-converting enzyme 2 (tACE2 and sACE2); Angiotensin II (ANG II); Angiotensin 1-7 (ANG 1-7) and angiotensin receptor 1 (AT1R) activation levels. Additionally, we hypothesize that an early peak in ANG II and ADAM-17 might represent a physiological attempt to reduce viral infection via tACE2. This viewpoint presents: (1) a brief introduction regarding the renin-angiotensin-aldosterone system (RAAS), detailing its receptors, molecular synthesis, and degradation routes; (2) a description of the proposed early changes in the RAAS in response to SARS-CoV-2 infection, including biological scenarios for the best and worst prognoses; and (3) the physiological pathways and reasoning for changes in the RAAS following SARS-CoV-2 infection.

Imaging studies have shown abnormal amygdala function in patients with posttraumatic stress disorder (PTSD). In addition, alterations in synaptic plasticity have been associated with psychiatric disorders and previous reports have indicated alterations in the amygdala morphology, especially in basolateral (BLA) neurons, are associated with stress-related disorders. Since, some individuals exposed to a traumatic event develop PTSD, the goals of this study were to evaluate the early effects of PTSD on amygdala glucose metabolism and analyze the possible BLA dendritic spine plasticity in animals with different levels of behavioral response. We employed the inescapable footshock protocol as an experimental model of PTSD and the animals were classified according to the duration of their freezing behavior into distinct groups: “extreme behavioral response” (EBR) and “minimal behavioral response”. We evaluated the amygdala glucose metabolism at baseline (before the stress protocol) and immediately after the situational reminder using the microPET and the radiopharmaceutical ¹⁸F-FDG. The BLA dendritic spines were analyzed according to their number, density, shape and morphometric parameters. Our results show the EBR animals exhibited longer freezing behavior and increased proximal dendritic spines density in the BLA neurons. Neither the amygdaloid glucose metabolism, the types of dendritic spines nor their morphometric parameters showed statistically significant differences. The extreme behavior response induced by this PTSD protocol produces an early increase in BLA spine density, which is unassociated with either additional changes in the shape of spines or metabolic changes in the whole amygdala of Wistar rats.

The posterodorsal medial amygdala (Me PD ) is a sexually dimorphic area and plays a central role in the social behavior network of rats. Dendritic spines modulate synaptic processing and plasticity. Here, we compared the number and structure of dendritic spines in the Me PD of prepubertal males and females and postpubertal males with and without sexual experience. Spines were classified and measured after three‐dimensional image reconstruction using DiI fluorescent labeling and confocal microscopy. Significantly differences are as follows: (a) Prepubertal males have more proximal spines, stubby/wide spines with long length and large head diameter and thin and mushroom spines with wide neck and head diameters than prepubertal females, whereas (b) prepubertal females have more mushroom spines with long neck length than age‐matched males. (c) In males, the number of thin spines reduces after puberty and, compared to sexually experienced counterparts, (d) naive males have short stubby/wide spines as well as mushroom spines with reduced neck diameter. In addition, (e) sexually experienced males have an increase in the number of mushroom spines, the length of stubby/wide spines, the head diameter of thin and stubby/wide spines and the neck diameter of thin and mushroom spines. These data indicate that a sexual dimorphism in the Me PD dendritic spines is evident before adulthood and a spine‐specific remodeling of number and shape can be brought about by both puberty and sexual experience. These fine‐tuned ontogenetic, hormonally and experience‐dependent changes in the Me PD are relevant for plastic synaptic processing and the reproductive behavior of adult rats.